There has been known an air discharge structure for a motorcycle which has a radiator cover. See, for example, Japanese Patent Laid-open No. 2000-118464 (pages 2 to 4, FIG. 1, hereinafter “patent document 1”).
FIG. 1 of patent document 1 will be described below with reference to FIG. 8 shown below. The reference numerals are assigned anew. FIG. 8 is a side elevational view showing a conventional air discharge structure for a motorcycle. A side area of a radiator 101 is covered with a radiator cover 102, which mixes discharged air from the radiator 101 and fresh air introduced from an inlet port defined in an upper front portion of the radiator cover 102, and emits the mixed air rearwardly of the radiator cover 102. The reference numeral 104 represents a horizontally opposed engine, and 105 carburetors for supplying a fuel to the horizontally opposed engine 104.
The radiator cover 102 is effective to utilize hot air from the radiator 101 and improve the appearance by covering the side area of the radiator 101. However, if there is not much ram air available, then since a high temperature rise occurs in the radiator cover 101, it is necessary to promote the discharging of air from within the radiator cover 102.
As the radiator cover 102 is shaped to cover the side area of the radiator 101 and only part of the carburetors 105 behind the radiator 101, the radiator cover 102 leaves the rear carburetors 105 exposed and is not effective enough to improve the appearance. Particularly, on American-type motorcycles (called “custom motorcycles”), the radiator cover 102 does not match surrounding parts in appearance, and is required to be better blended and harmonized with the engine, the vehicle frame, and the fuel tank around the radiator cover 102.